Transition metal mixed hydroxides have been used as raw materials for positive electrode active materials in nonaqueous electrolyte secondary batteries such as lithium secondary batteries. Lithium secondary batteries have already been put to practical use as small-sized power sources such as cellular phone applications, and notebook computer applications, and moreover their application has been attempted also in large-sized power sources such as automobile applications, and electric power storage applications.
Patent Document 1 has specifically disclosed, as a conventional transition metal mixed hydroxide, a transition metal mixed hydroxide made from Ni and Mn as main ingredients, wherein the content of SO4 is 730 ppm by weight and the content of an alkali metal is 1700 ppm by weight.